With rapid development of wireless communication techniques, conflicts between increasing wideband wireless communication requirements and limited spectrum resources become more and more apparent. Conventional spectrum management techniques allocate spectrum resources in a relative fixed manner and cannot adjust the allocation rapidly and adaptively with requirements. Although digital signal processing techniques such as multiple input multiple output (MIMO) and high level modulation may increase a spectrum utilization ratio, the problem that the spectrum resources are limited cannot be solved. Many spectrum resources allocated to existing wireless communication systems have idle spectrums, which blocks the access of potential wireless communication systems.
Based on the above, cognitive radio (CR) technique attracts people's eyes. The idea of the CR technique is: without affecting normal operation of an authorized system on an authorized frequency band, a wireless communication device with a cognitive function access an idle spectrum of the authorized frequency band in an opportunistic manner and dynamically uses the spectrum. Thus, the wireless communication device is able to find an idle spectrum and utilize the idle spectrum reasonably. The problem of unreasonable utilization of the spectrum resources due to fixedly allocation of the spectrum may be solved.
In the CR technique, the obtaining of the idle spectrum is a premise of the normal operating of the wireless communication system. The wireless communication system has to ensure the accuracy of the idle spectrum obtained, so as to avoid harmful interference to the authorized system. In addition, the wireless communication system needs to decrease the complexity for obtaining the idle spectrum and reduce system overhead as much as possible, so as to reduce the implementation complexity and cost of the wireless communication system.
In an existing technique, the obtaining of the idle spectrum is realized through spectrum sensing. A wireless communication system (e.g., LTE) deployed on an authorized frequency band determines whether the authorized frequency band is occupied by the authorized system through detecting an energy or signal characteristic of the authorized system, so as to identify the idle spectrum of the authorized frequency band in a specific time domain and a specific space domain. Thus, the wireless communication system can access the idle spectrum and maintains idle spectrum information.
Currently, there are a single-node-based spectrum sensing technique and a cooperative spectrum sensing technique. In the single-node-based spectrum sensing technique, a sense node of the wireless communication system determines whether the authorized frequency band is occupied by the authorized system through detecting the energy or signal characteristic of the authorized system, and then obtains the idle spectrum on the authorized frequency band. This sense result is effective within a small area. In the cooperative spectrum sensing technique, multiple adjacent sense nodes of the wireless communication system sense the same frequency band within the authorized frequency band. The sensed results of the cooperative sense nodes are combined. The combined result is effective within a small area.